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Fig. 7 | Microbial Cell Factories

Fig. 7

From: Efficient protection of microorganisms for delivery to the intestinal tract by cellulose sulphate encapsulation

Fig. 7

Release of encapsulated bacteria in vivo. a After overnight culture of E. coli-LUX or encapsulation of overnight pre-cultures, the free or CS encapsulated E. coli-LUX were freeze dried and stored before rehydration and either direct titration or decapsulation followed by titration to determine the CFU per mL or per capsule. E. coli-LUX containing capsules after rehydration are shown in (b) ×40 magnification and (c) ×100 magnification. After decapsulation the E. coli-LUX bacteria were plated on agar plates and the titre determined (d). The number of capsules or amount of free bacteria equivalent to 2.7 × 109 CFU or 5.3 × 109 CFU was administered to mice by oral gavage. 2 h, 4 h and 24 h post gavage feces were harvested and 24 h after gavage the animals were euthanized and stomach, cecum and colon harvested. These organs, as well as the feces were placed in individual wells of six well plates and exposed to the emission spectrum of luciferase for 10 s, 1, and 2 min. e Four mice were administered 2.7 × 109 CFU of free E. coli-LUX (M1) (left most six well plate), 5.3 × 109 CFU of free E. coli-LUX (M2) (six well plate second from left), 2.7 × 109 CFU of encapsulated E. coli-LUX (M3) (six well plate third from left) or 5.3 × 109 CFU of encapsulated E. coli-LUX (M4) (rightmost six well plate) by oral gavage. 2 h, 4 h and 24 h post gavage feces were harvested and 24 h after gavage the animals were euthanized and stomach, cecum and colon harvested. These organs, as well as the feces were placed in individual wells of six well plates and exposed to the emission spectrum of luciferase for 10 s, 1, and 2 min. Here the results from 2 min exposure are shown. The bioluminescence was measured with an open filter. The signal was visualized as pseudo color images indicating light intensity (red being the most intense and blue the least intense), which are superimposed over the grayscale reference photographs. f The bioluminescence signal from the gavage experiment described above was quantitated using Living Image 4.4 software. The signal from stomach, cecum, colon, 2 h feces, 4 h feces and 24 h feces from mice administered 2.7 × 109 CFU of free E. coli-LUX (M1) (blue bars), 5.3 × 109 CFU of free E. coli-LUX (M2) (orange bars), 2.7 × 109 CFU of encapsulated E. coli-LUX (M3) (grey bars) or 5.3 × 109 CFU of encapsulated E. coli-LUX (M4) (yellow bars) is shown.

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